[Pw_forum] vc-relax of arsenate doped gypsum

[Nicola Marzari]

On 03/12/2014 14:54, Shaofeng Wang wrote:
> Dear QE users,
>
> I am optimizing the geometry of arsenate doped gypsum. The primitive cell
> is used for calculation.
> Firstly, I optimized the structure of gypsum using norm-conserving
> pseudopotential with ecutoff of 100ry. The input file is shown as follow:
>    &CONTROL


you could try keeping it neutral, after the arsenic substitution,
or keep the original sulfur, but have a charge of -1.

probably your supercell is too small to accommodate a charge of -1.

			nicola

----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL